@ArdiL: No thanks needed - it sounds like you found the answer yourself (i.e. changing the coding on 2 x additional Leuchte-sets - Leuchte16BLK and Leuchte17TFL). On the version of tail-light fittings on the picture in my link, these 2 x Leuchte-sets are used to operate the second (inner) turn-signal lamps!
Anyhow, well done - and thank you for sharing your work with the forum community (that's what forums are meant to do)! I've added your tweak to the mkVII-vcds-tweak-reference-thread as acknowledgement for your generous contribution!
My responses to your questions below:
Question 1 - Alas No, the reversing light is a bog-ordinary lamp. The color of this light is predetermined by the physical lamp (this lamp is NOT like your front DRL/Turn-signal lamp)!
Question 2 - hmm...I would be extremely surprised (flabbergasted, in fact) if the "empty slots" were populated with actual lamps. Vehicles that roll-off the VW assembly-line are renowned for being "production efficient" - meaning that the amount of copper/equipment in these cars is just sufficient to provide for the options that the buyer paid-for (ain't no profit for VW shareholders in supplying more than the bare minimum :cool:)!
Question 3: Same response as in Question 2!
Don
PS: is there any way that you can add the Leuchte-set assignments to the 1st picture in post #1881? I reckon this your add greatly to your already excellent post!